Aspartate aminotransferase is an enzyme that catalyzes the production of aspartic acid from oxaloacetic acid and glutamic acid. While aromatic amino acid aminotransferase is known as another enzyme that catalyzes the synthesis of aspartic acid from oxaloacetic acid and glutamic acid in Escherichia coli, the synthesis of aspartic acid is thought to be achieved mainly by aspartate aminotransferase (Non-patent Document 1).
The biochemical properties of the aspartate aminotransferase of microorganisms of the genus Escherichia are known, and the aspC gene that encodes for the enzyme is also known (Non-patent Document 2). It is also known that by overexpressing the aspC gene of a microorganism of the genus Escherichia, the L-amino acid productivity can be improved (Patent Documents 1 and 2).
Proteins in living organisms are polymers of α-amino acids, and basically L-amino acids are the constituents of the protein. Many L-amino acids, in addition to being important as constituents of living organisms, exhibit bioactivity or pharmacological activity per se, or have a flavoring effect or a nutritive effect; a wide variety of use applications, including pharmaceuticals, foods and the like, have been developed.
However, no report is available stating or suggesting that L-amino acid production efficiency can be improved by decreasing or deleting aspC activity in the fermentative production of L-amino acids.